Page 2209 of 4323

I28576
270°
Bright
0°
DarkR6
ILL±
I28577
Light Control Rheostat
Wire Harness View:
R6
E
± DIAGNOSTICSAUDIO SYSTEM
DI±2007
2201 Author: Date:
2005 SEQUOIA (RM1146U)
8 Check light control rheostat.
PREPARATION:
(a) Reconnect the light control rheostat switch connector.
(b) Ignition switch is ON.
(c) Light control switch is TAIL or HEAD.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Symbol
(Tester connection)ConditionSpecified condition
ILL± (R6±6) ±
Body groundRheostat knob to fully
counterclockwise "
fully clockwise
Below 1 V " 10 to 14 V
NG Replace light control rheostat.
OK
9 Check harness and connector (Light control rheostat ± Body ground).
PREPARATION:
Disconnect the light control rheostat connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol (Tester connection)Specified condition
E (R6±5) ± Body groundBelow 1 W
NG Repair or replace harness or connector.
OK
Repair or replace wire harness or connector (Battery ± spiral cable sub±assy).
Page 2210 of 4323
I28378
Radio Receiver Assy
R±W 17
R4
MUTE S10
Stereo Component Amplifier
MUTE DI±2008
± DIAGNOSTICSAUDIO SYSTEM
2202 Author: Date:
2005 SEQUOIA (RM1146U)
Mute signal circuit
CIRCUIT DESCRIPTION
This circuit sends a signal to the stereo component amplifier to mute noise. Because of that, the noise pro-
duced by changing the sound source ceases.
If there is an open in the circuit, noise can be heard from the speakers when changing the sound source.
If there is a short in the circuit, even though the stereo component amplifier assy is normal, no sound or only
an extremely small sound can be produced.
WIRING DIAGRAM
DID9Y±01
Page 2211 of 4323

I28755
Stereo Component Amplifier Assy:
MUTE
S10
I28606
Radio Receiver Assy
Wire Harness View:
MUTE
R4
I28752
Stereo Component Amplifier Assy:
MUTE
S10
± DIAGNOSTICSAUDIO SYSTEM
DI±2009
2203 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Inspect stereo component amplifier assy.
PREPARATION:
Make sure that the stereo component amplifier assy connector
is connected.
CHECK:
Measure the voltage according to the value in the table below.
OK:
Symbol
(Tester connection)ConditionSpecification
MUTE (S10±1) ±
Body groundTurn ignition switch to
ACC, Audio system is
playing "Changing mode
Above 3.5 V " Below 1 V
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±1967).
NG
2 Check harness and connector (Radio receiver assy ± Stereo component amplifi-
er assy).
PREPARATION:
Disconnect the radio receiver assy and stereo component am-
plifier assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
MUTE (R4±7) ±
MUTE (S10±1)AlwaysBelow 1 W
MUTE (R4±7) ±
Body groundAlways10 kW or higher
NG Repair or replace harness or connector.
Page 2212 of 4323
I28738
R4 Wire Harness View:
MUTE
DI±2010
± DIAGNOSTICSAUDIO SYSTEM
2204 Author: Date:
2005 SEQUOIA (RM1146U)
OK
3 Inspect radio receiver assy.
PREPARATION:
Reconnect the radio receiver assy connector.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:
Symbol
(Tester connection)ConditionSpecified condition
MUTE (R4±7) ±
Body groundIgnition switch ONAbove 3.5 V
OK Replace stereo component amplifier assy.
NG
Replace radio receiver assy.
Page 2213 of 4323
I28505
WRadio Receiver Assy
G 429
8
R B
R4L+
L± Stereo Component
Amplifier Assy
R+
R±
GND 19
18
10 3
S10
5
Shielded L+
L± R+
R±S10
S10
S10
S106R4
R4
R4
R4 SGND
± DIAGNOSTICSAUDIO SYSTEM
DI±2011
2205 Author: Date:
2005 SEQUOIA (RM1146U)
Sound signal circuit
CIRCUIT DESCRIPTION
The radio receiver assy sends a sound signal to the stereo component amplifier assy through this circuit.
The sound signal that has been sent is amplified by the stereo component amplifier assy, and then sent to
the speakers.
If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunc-
tion in the stereo component amplifier assy or the speakers.
WIRING DIAGRAM
DID9Z±01
Page 2214 of 4323
I28739
Radio Receiver Assy
Wire Harness View:
R4
L±
L+ R+ R±
I28752
Stereo Component Amplifier Assy
Wire Harness View:
L+
R±L±
R+
S10
DI±2012
± DIAGNOSTICSAUDIO SYSTEM
2206 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check harness and connector (Radio receiver assy ± Stereo component amplifi-
er assy).
PREPARATION:
Disconnect the radio receiver assy and stereo component am-
plifier assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol (Tester connection)Specified condition
L+ (R4±9) ± L+ (S10±3)Below 1 W
L± (R4±19) ± L± (S10±2)Below 1 W
R+ (R4±8) ± R+ (S10±5)Below 1 W
R± (R4±18) ± R± (S10±4)Below 1 W
L+ (R4±9) ± Body ground10 kW or higher
L± (R4±19) ± Body ground10 kW or higher
R+ (R4±8) ± Body ground10 kW or higher
R± (R4±18) ± Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Proceed to next circuit inspection shown in problem symptoms table (See page DI±1967).
Page 2215 of 4323
± DIAGNOSTICSAUDIO SYSTEM
DI±2013
2207 Author: Date:
2005 SEQUOIA (RM1146U)
Speaker circuit
CIRCUIT DESCRIPTION
The sound signal that has been amplified by the stereo component amplifier is sent to the speakers from
the stereo component amplifier through this circuit.
If there is a short in this circuit, the stereo component amplifier assy (built±in amp) detects it and stops output
to the speakers.
Thus sound cannot be heard from the speakers even if there is no malfunction in the stereo component am-
plifier assy (built±in amp) or the speakers.
DIDA0±01
Page 2216 of 4323
I28503
Stereo Component
Amplifier Assy
IB1 S9 T12
Tweeter RH
F14 Front Door Speaker
and Woofer LH
F15 Front Door Speaker
and Woofer LH
T13
Tweeter RHII2
J/C
BC1
BA1 R10
Rear Door
Speaker RH
R9
Rear Door
Speaker LHJ/C BC1
BA1II2
II2
II2
J49 J48
J49 J48
J34 J33
J34 J33IB1
IB1
IB1S9
S9
S9
S9
S9
S9
S9
S9
S9
S9
S9FL±
WFL+
WFR±
FR+
RR+
RL+ FL+
WFL±
WFR+
FR±
RR±
RL± 11
2
6
17
18
7
3
5 12
14
4
13 2
3 4
1 31
2 4
23
4 1
2
3 4
15
4
6
7
2
1
10
9
11 12
11 12 2 1
2 1I
C
HB
KE
LF V
P
G
L±W LRV
P
G L±W
R Y
L LGR Y
L LG V
P
R
WR
WR
W
Y B
Y B
Y B Separate Type Amplifier: DI±2014
± DIAGNOSTICSAUDIO SYSTEM
2208 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM